CODEWITHSUNDEEP
pythonraspberry-pimicrocontroller
Eureka
Eureka

Reputation: 93

Raspberry Pi - run function for 5 seconds

I'm trying to get my Raspberry Pi to blink a LED for 5 seconds, and then another one for 5 seconds as well. So I have two functions, one for blinking my red LED, and another for the blue one. I used utime.sleep(0.5) for the functions to turn off the LEDs every half second.

def blink_red():
  RED.toggle()
  BLUE.value(0)
  utime.sleep(0.5)

def blink_blue():
  BLUE.toggle()
  RED.value(0)
  utime.sleep(0.5)

For the execution of the code, I made use of utime.sleep(5) in hopes of getting each function to run for 5 seconds, however it doesn't make the LEDs blink. It turns the red led on for five seconds, and the blue one on for 5 seconds as well.

while True:
  blink_red()
  time.sleep(5)
  blink_blue()
  utime.sleep(5)

Which parts of my code do I need to change or is there a more pythonic way of doing this?

Edit: I am running micropython

Upvotes: 0

Views: 834

Answers (1)

larsks
larsks

Reputation: 312410

It turns the red led on for five seconds (while the blue one is off), and then turns the blue one on for 5 seconds (while red is off as well).

It sounds like your code is doing what you've asked it do do.

  1. Your loop is running:

      blink_red()
  time.sleep(5)
  blink_blue()
  utime.sleep(5)

  2. When you call blink_red():

      # you toggle the RED LED (once)
  RED.toggle()

  # you turn off the blue LED
  BLUE.value(0)

  # you wait 0.5 seconds
  utime.sleep(0.5)

  # ...and then you return to the main loop

  3. Now you're back in the loop, and you call time.sleep(5).

Do you see where this is going?

If you wanted blink_red() to blink the red LED for five seconds, you would need something like:

def blink_red():
    BLUE.off()
    for i in range(5):
        RED.toggle()
        utime.sleep(0.5)
        RED.toggle()
        utime.sleep(0.5)

And your while loop would look like this:

while True:
  blink_red()
  blink_blue()

(Assuming that you rewrote blink_blue as well.)

Here's a complete program; I was running this using micropython on an ESP C3 (so it's possible it will have slightly different syntax than micropython on the Pi, but it should be largely the same):

try:
    import time
except ImportError:
    import utime as time

from machine import Pin


RED = Pin(3, Pin.OUT)
BLUE = Pin(5, Pin.OUT)

PINS = [RED, BLUE]


def blink_pin(pin):
    for i in range(5):
        pin.on()
        time.sleep(0.5)
        pin.off()
        time.sleep(0.5)


# ensure everything is off to start
for pin in PINS:
    pin.off()

while True:
    blink_pin(RED)
    blink_pin(BLUE)

Upvotes: 2

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